From OMIM
Refsum disease is an autosomal recessive inborn error of lipid metabolism classically characterized by a tetrad of clinical abnormalities: retinitis pigmentosa, peripheral neuropathy, cerebellar ataxia, and elevated protein levels in the cerebrospinal fluid (CSF) without an increase in the number of cells. However, not all patients show all these features. All patients have accumulation of an unusual branched-chain fatty acid, phytanic acid, in blood and tissues. Other variable features include cardiac dysfunction, nerve deafness, ichthyosis, and multiple epiphyseal dysplasia (review by Skjeldal et al., 1987). Increased levels of phytanic acid can also be found in peroxisomal biogenesis disorders; see Zellweger syndrome (see 214100) (Skjeldal et al., 1987). Infantile Refsum disease (see PBD1B, 601539) is a distinct disorder with a different phenotype and genetic basis. A phenotype clinically indistinguishable from that of classic Refsum disease (PBD9B; 614879), but with a different biochemical profile, can be caused by mutation in the gene encoding peroxin-7 (PEX7; 601757) on chromosome 6q.  http://www.omim.org/entry/266500

From MedlinePlus Genetics
Refsum disease is an inherited condition that causes vision loss, absence of the sense of smell (anosmia), and a variety of other signs and symptoms.

The vision loss associated with Refsum disease is caused by an eye disorder called retinitis pigmentosa. This disorder affects the retina, the light-sensitive layer at the back of the eye. Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. The first sign of retinitis pigmentosa is usually a loss of night vision, which often becomes apparent in childhood. Over a period of years, the disease disrupts side (peripheral) vision and may eventually lead to blindness.

Vision loss and anosmia are seen in almost everyone with Refsum disease, but other signs and symptoms vary. About one-third of affected individuals are born with bone abnormalities of the hands and feet. Features that appear later in life can include progressive muscle weakness and wasting; poor balance and coordination (ataxia); hearing loss; and dry, scaly skin (ichthyosis). Additionally, some people with Refsum disease develop an abnormal heart rhythm (arrhythmia) and related heart problems that can be life-threatening.  https://medlineplus.gov/genetics/condition/refsum-disease